182 C. M. CHILD 



tion in the organism at the different temperatures. If the coeffi- 

 cient of distribution were the most important factor, the resist- 

 ance would be lower at the higher temperature. As a matter of 

 fact, the animals with the higher rate of reaction determined by 

 the higher temperature become more readily and more completely 

 acclimated and therefore live longer. 



Taken as a whole, the evidence from temperature experiments 

 with alcohol and KCN for the existence of a relation between 

 physiological resistance and rate of reaction is highly conclusive. 

 Within certain limits, the higher the temperature, the higher the 

 rate of reaction, the less the resistance by the direct method, and 

 the greater the resistance by the indirect method. 



How far these relations will hold for the higher animals, and 

 particularly those in which the nervous system contains a large 

 amount of lipoid material, can be determined only by experiment. 

 x4.t present I can state that they hold for all flatworms that have 

 been tested, some five species, for Corymorpha palma among the 

 coelenterates and for early embi-yonic stages of various species, 

 so far as tested, including the amphibia. 



S. Temperature experiments with benzamid 



On page 179 above, attention was called to the bearing upon the 

 question of the relation between resistance and rate of reaction 

 of experiments with a substance whose coefficient of distribu- 

 tion between water and fat increases as the temperature falls. 

 In temperature experiments with such a substance the animals 

 should die earlier at the lower temperature if the coefficient of 

 distribution or some other factor similarly affecting its concen- 

 tration in the cell is the chief factor in its effect, but if the rate of 

 reaction 'in the organism is the chief factor, then the animals 

 should die earlier at the higher temperature in spite of the lower 

 coefficient of distribution at this temperature. 



The coefficient of distribution of benzamid as determined , by 

 Meyer is 0.672 at 3°C. and 0.437 at 36°C. (Meyer '01, pp. 341- 

 344). In accordance with this difference in the coefficient of 

 distribution, Meyer found that the minimal concentration which 

 would produce complete narcosis in tadpoles was s^o m. at 



